> They want to correlate my online activities with my offline identity.
It seems to me that the only legitimate use of circles is with respect to people you are sharing with that you know in real life. If you want to talk to total strangers, then you want to be pseudonymous but you also have almost no reason to not post publicly.
That's fine; there is twitter, tumblr, even HN fit that model. All pseudonymous posts, all public all the time. Discussions with strangers.
Google+ can be used that way; I guess many people do. I somehow got marked as a redditor when I first signed up and I still have about 3 redditors that are strangers start following me every week, and I think it's pretty awful.
There is a huge space for online interactions with people who you know in meatspace, and plenty of reason why Google would want to get into that game. Product recommendations is the first thing that comes to mind; would you rather buy an item that your real life friend says is good or that a random person on the internet says is good? That is a benefit both to you and to google if they can provide that.
If you don't want to interact with people you know IRL, there are plenty of other services besides Google+ available online. Gmail remains one of them, it's a perfectly legitimate service to interact with strangers. It seems to me that you are throwing out the baby with the bathwater just because they are offering a product that you don't want to use, but that's obviously your choice.
> The only reason that it would take months to implement is because they're using some authoritative method - maybe ISP customer info, or government supplied info- to correlate users to reveal real identity.
This is seriously bordering on "batshit crazy" level conspiracy theory. What you are describing is impossible on so many levels; legal, technical and PR. I have no idea what they are implementing, but it's probably more along the lines of allowing people who are demonstrably known in real life by pseudonyms (like Lady Gaga, but less famous). The advantage is not from you using your real name, the advantage is from knowing the name that lots of people already know you by so all those people can easily find you on Google+. No one you know in real life would be able to find you on HN unless you specifically linked them to your profile; which again is fine, it is simply providing a different service, one where you could be talking to your best friend and never even know it.